Iowa City straddles the Iowa River, which famously flooded catastrophically in June 2008 — inundating the University of Iowa campus, the Hancher Auditorium, and hundreds of residences. Ralston Creek, which runs through the older east-side neighborhoods, also floods during intense summer thunderstorms when urban storm drains are overwhelmed. Iowa City's humid continental climate produces heavy spring snowmelt and intense June–July thunderstorm events that keep basement sump pumps running nearly continuously from March through July.
High-risk neighborhoods
Manville Heights and Idyllwild neighborhoods adjacent to the Iowa River were among the hardest hit in the 2008 flood and remain in FEMA Special Flood Hazard Areas; Goosetown-area homes along Ralston Creek face recurring basement sewer backup during intense summer thunderstorms that overwhelm the older combined storm-sanitary sewer system.